openstack/openstack-ansible
Code Issues Proposed changes
7a12374003
openstack-ansible/doc/source/install-guide/configure-swift-policies.rst
Jesse Pretorius 7a12374003 Various Documentation Updates 
This patch does the following:

- Move the CONTRIBUTING doc content into the developer documentation
- Move the development-stack doc content into the developer documentation
- Rename all instances of 'OpenStack Ansible' to 'OpenStack-Ansible'
- Implements a simpler navigation index for the bottom of the page
- Implements a navigation index at the bottom of all developer docs
- Updates the README to reflect where to get documentation and further
  information
- Adds more information into the 'scripts' developer doc
- Updates the 'Additional Resources' Appendix with Ansible information

Change-Id: Ic08ba072f3b3d1e4e446d1e81c20c0cdf01833de
2015-10-05 18:16:01 +01:00

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Home OpenStack-Ansible Installation Guide

Storage Policies

Storage Policies allow segmenting the cluster for various purposes through the creation of multiple object rings. Using policies, different devices can belong to different rings with varying levels of replication. By supporting multiple object rings, Object Storage can segregate the objects within a single cluster.

Storage policies can be used for the following situations:

  • Differing levels of replication: A provider may want to offer 2x replication and 3x replication, but does not want to maintain two separate clusters. They can set up a 2x policy and a 3x policy and assign the nodes to their respective rings.
  • Improving performance: Just as solid state drives (SSD) can be used as the exclusive members of an account or database ring, an SSD-only object ring can be created to implement a low-latency or high performance policy.
  • Collecting nodes into groups: Different object rings can have different physical servers so that objects in specific storage policies are always placed in a specific data center or geography.
  • Differing storage implementations: A policy can be used to direct traffic to collected nodes that use a different disk file (for example, Kinetic, GlusterFS).

Most storage clusters do not require more than one storage policy. The following problems can occur if using multiple storage policies per cluster:

  • Creating a second storage policy without any specified drives (all drives are part of only the account, container, and default storage policy groups) creates an empty ring for that storage policy.
  • A non-default storage policy is used only if specified when creating a container, using the X-Storage-Policy: <policy-name> header. After the container is created, it uses the created storage policy. Other containers continue using the default or another storage policy specified when created.

For more information about storage policies, see: Storage Policies